Scientists estimate total weight of plastic floating in world's oceans: Nearly 269,000 tons of plastic pollution floating in the ocean

Model results for global count density in four size classes. Model prediction of global count density (pieces km−2; see colorbar) for each of four size classes (0.33–1.00 mm, 1.01–4.75 mm, 4.76–200 mm, and >200 mm). Credit: Marcus Eriksen et al, PLoS ONE, 2014; DOI: 10.1371/journal.pone.0111913

Nearly 269,000 tons of plastic pollution may be floating in the world's oceans, according to a study published December 10, 2014 in the open-access journal PLOS ONE by Marcus Eriksen from Five Gyres Institute and colleagues.

Microplastic pollution is found in varying concentrations throughout the oceans, but estimates of the global abundance and weight of floating plastics, both micro and macroplastic, lack sufficient data to support them. To better estimate the total number of plastic particles and their weight floating in the world's oceans, scientists from six countries contributed data from 24 expeditions collected over a six-year period from 2007-2013 across all five sub-tropical gyres, coastal Australia, Bay of Bengal, and the Mediterranean Sea. The data included information about microplastics collected using nets and large plastic debris from visual surveys, which were then used to calibrate an ocean model of plastic distribution.

Based on the data and model, the authors of the study estimate a minimum of 5.25 trillion plastic particles weighing nearly 269,000 tons in the world's oceans. Large plastics appear to be abundant near coastlines, degrading into microplastics in the 5 subtropical gyres, and that the smallest microplastics were present in more remote regions, such as the subpolar gyres, which the authors did not expect. The distribution of the smallest microplastics in remote regions of the ocean may suggest that gyres act as 'shredders' of large plastic items into microplastics, after which they eject them across the ocean.

"Our findings show that the garbage patches in the middle of the five subtropical gyres are not the final resting places for the world's floating plastic trash. The endgame for micro-plastic is interactions with entire ocean ecosystems," says Marcus Eriksen, PhD, Director of Research for the 5 Gyres Institute.

Source: PLOS

Home on the range: Cattle ranching in the Amazon

Rubber tapper children ride their steer home from school in the Brazilian state of Acre.
Credit: Image courtesy of University of California - Santa Barbara

In a paper published in the current issue of the journal Human Organization, UC Santa Barbara anthropologist Jeffrey Hoelle takes a look at the rise of cattle ranching in the Brazilian state of Acre and the processes that brought it to one of the greenest corners of western Amazonia.

According to Hoelle, an assistant professor of anthropology, the Amazonian research on cattle usually falls into one of two camps: documentation of the environmental consequences of cattle raising -- the leading driver of Amazonian deforestation -- or analysis of the ways that policies and markets interact to make cattle and pasture more profitable than the standing forest. His article aims to expand the study of Amazonian cattle raising to include "cattle culture," the positive cultural constructions associated with a cattle-raising lifestyle that contribute to its appeal over other ways of using the land.

In Acre, Hoelle writes, "the rubber tapper movement protested the arrival of cattle ranching in the 1980s, capturing worldwide attention with a message of sustainable forest-based development. Across Amazonia, groups who once opposed or were displaced by cattle are now adopting it, including Acrean rubber tappers and colonists."

Using primary data he collected among rural and urban groups in Acre, Hoelle demonstrates, through a discussion of two processes that result in very different types of cultural expression, how cattle culture emerged in this unlikely place.

On the one hand, he notes, the subsistence uses of cattle led to cultural beliefs that were based on interdependence and resembled cattle complexes from other parts of the world. Yet local economic relationships with cattle could not explain the explosion of a "cauboi" (cowboy) model in which human control of cattle and nature was celebrated by men and women with shiny belt buckles, tight jeans, boots and a love of rodeos and "sertananeja" or "contri" (country) music.

Rubber tapper Jatobá Rocha was hesitant about cattle when Hoelle first met him in 2007. A year later, however, he bought a young bull named Tchoa, who quickly became a member of the family, pulling his own weight -- literally, with an oxcart -- and serving as a means of transportation for the Rochas.

Hoelle explained that people raise cattle all over the world in different ways, from subsistence pastoralism in East Africa to large-scale capitalist ranching in the Americas, with smallholders who fall somewhere in between these economic and ecological systems. In traditional nomadic pastoralism, humans regarded their cattle as individuals -- as the Rochas do Tchoa -- and develop an emotional connection with them. With large-scale ranching, cattle are a nameless commodity.

"For the cowboys and ranchers, the objective is to raise cattle as if they were a crop to be harvested at the right time," Hoelle said. "You don't want to hurt the herd to the extent that you'll jeopardize your investment, but you do need to dominate it." This economic relationship is recreated symbolically in rituals such as rodeos, he noted.
"If, however, you're relying on a cow for its milk, or if you're going to ride it to the store, you have to establish a relationship with the animal," he continued. Deep cultural connections form from that relationship, such as India's "sacred cow" or the cattle complex in East Africa. Hoelle argued the same thing happens deep in the heart of capitalist ranching in the Amazon.

He emphasized that it isn't necessarily ranching/pastoralism or capitalism/subsistence that explains the type of cattle culture that emerges, but rather the type of relationship that humans have with animals to secure products or services from them. "This really became apparent when I stopped looking at the ways that cowboys roughed up the cattle and focused instead on the affection they showed their horses," Hoelle continued. "They'd name their horses, hug them around the neck and nudge them playfully, and probably punch you if you asked about eating their beloved equine."

For the cowboys, horses were essential economic tools for securing the production of cattle; whereas for smallholders, the cattle served a similar function in terms of daily reliance. In both cases, cultural beliefs develop to protect vital resources.

Since the arrival of cattle in Acre, Hoelle said, these animals have been surrounded by violence, deforestation and displacement. "It is surprising that cattle raising and cattle culture have expanded across Amazonia, and especially in Acre," he commented. "It is also troubling for those of us concerned with sustainable alternatives to cattle raising. My point is that you have to put that aside for the moment and attempt to understand why it makes sense for those adopting it."

Understanding the appeal of the cowboy in the Amazon rainforest is critical to understanding the appeal of cattle raising, he noted. "The cowboy persona is something people strive for. It's very strong there, and really important in terms of the way people interact with nature," Hoelle said. "Being the strong manly type who can face the forest and transform it into this nice uniform pasture full of big domesticated animals is very powerful in the way it communicates ideals of masculinity, modernity and development."

From a distance of thousands of miles, it's easy for us here in the U.S. to decry the Acreans' decimation of the rainforest to expand cattle-grazing land. Our instinct is to preserve the rainforest because of its vital contribution to the world. "But those who are living it see themselves in the same way pioneers and settlers have throughout history. There is a drive to tame the frontier -- to control or cultivate nature," Hoelle explained. While this tendency has declined in the U.S., it remains front and center for those attempting to make a living in a place where people really do feel that they are under constant assault from the forest, he noted. In this context, the cowboy is an appealing figure, while here it might be more common to romanticize the Indians.

Hoelle, the author of the forthcoming book, "Rainforest Cowboys: The Rise of Ranching and Cattle Culture in Western Amazonia," emphasized that crafting appropriate policy solutions requires an understanding of the interlinked political, economic and cultural features of Amazonian cattle raising.

Source: University of California - Santa Barbara

Expect higher grass pollen, allergen exposure in coming century

A study provides the first evidence that pollen production is significantly stimulated by elevated carbon dioxide in a grass species as a result of climate change, which may have significant impact on human health. Credit: UMass Amherst

Results of a new study by scientists at the University of Massachusetts Amherst strongly suggest that there will be notable increases in grass pollen production and allergen exposure up to 202 percent in the next 100 years, leading to a significant, worldwide impact on human health due to predicted rises in carbon dioxide (CO2) and ozone (O3) due to climate change.

While CO2 stimulates reproduction and growth in plants, ozone has a negative impact on plant growth, the authors point out. In this study in Timothy grass, researchers led by environmental health scientist Christine Rogers of the UMass Amherst School of Public Health and Health Sciences (SPHHS) determined the interactive effects of CO2 and ozone at projected higher levels on pollen production and concentrations of a Timothy grass pollen protein that is a major human allergen. Findings are reported in the current issue of PLOS ONE.

Rogers and plant science colleagues at UMass Amherst, with postdoctoral researcher and first author Jennifer Albertine, write, "The implications of increasing CO2 for human health are clear. Stimulation of grass pollen production by elevated CO2 will increase airborne concentrations and increase exposure and suffering in grass pollen-allergic individuals."

Rogers notes that, "This is the first evidence that pollen production is significantly stimulated by elevated carbon dioxide in a grass species and has worldwide implications due to the ubiquitous presence of grasses in all biomes and high prevalence of grass pollen allergy. These results are similar to our other studies performed in other highly allergenic taxa such as ragweed but with more extreme outcomes and wider impacts."

For these experiments, the researchers exposed grass plants in specially designed continuously stirred tank reactor chambers that allow researchers to expose plants to different atmospheric gas concentrations. They established four experimental atmospheric treatments:

• control, current atmosphere (30 ppb O3 and 400 ppm CO2)
• elevated O3, current CO2 (80 ppb O3, 400 ppm CO2)
• current O3, elevated CO2 (30 ppb O3, 800 ppm CO2)
• elevated O3, elevated CO2 (80 ppb O3, 800ppm CO2)

At the appropriate plant development stage, Albertine and colleagues bagged flowers, captured and measured pollen amounts and extracted the allergen protein Phl p 5 from pollen samples for measurement by enzyme-linked immunosorbent assay (ELISA).

They found that elevated CO2 of 800 ppm, increased pollen production per flower by 53 percent while the different ozone levels had no effect on the amount of pollen produced. There was also a trend of increased number of plants flowering in response to elevated CO2 further increasing pollen production up to 200 percent. While elevated ozone did decrease the Phl p 5 allergen content in pollen, "the strong CO2-stimulation of pollen production suggests increased exposure to Timothy grass allergen overall," even if O3 projections are realized, the authors note.

They add that the health implications of increased ozone are "more complex" because higher levels of this greenhouse gas irritate mucous membranes and worsen the allergic airway response. Projected ozone increases "would likely elicit negative respiratory health effects independent of any health effects as a result of increased pollen by elevated CO2."

Source:  University of Massachusetts at Amherst

Massive study provides first detailed look at how Greenland's ice is vanishing

This NASA visualization shows the change in the surface elevation of the southeast region of the Greenland ice sheet between 2003 and 2012. Thinning ... [show more]
 Credit: NASA's Goddard Space Flight Center Scientific Visualization Studio

The Greenland Ice Sheet is the second-largest body of ice on Earth. It covers an area about five times the size of New York State and Kansas combined, and if it melts completely, oceans could rise by 20 feet. Coastal communities from Florida to Bangladesh would suffer extensive damage.

Now, a new study is revealing just how little we understand this northern behemoth.

Led by geophysicist Beata Csatho, PhD, an associate professor of geology at the University at Buffalo, the research provides what the authors think is the first comprehensive picture of how Greenland's ice is vanishing. It suggests that current ice sheet modeling studies are too simplistic to accurately predict the future contributions of the entire Greenland Ice Sheet to sea level rise, and that Greenland may lose ice more rapidly in the near future than previously thought.

"The great importance of our data is that for the first time, we have a comprehensive picture of how all of Greenland's glaciers have changed over the past decade," Csatho says.

"This information is crucial for developing and validating numerical models that predict how the ice sheet may change and contribute to global sea level over the next few hundred years," says Cornelis J. van der Veen, PhD, professor in the Department of Geography at the University of Kansas, who played a key role in interpreting glaciological changes.

The project was a massive undertaking, using satellite and aerial data from NASA's ICESat spacecraft and Operation IceBridge field campaign to reconstruct how the height of the Greenland Ice Sheet changed at nearly 100,000 locations from 1993 to 2012.

Ice loss takes place in a complex manner, with the ice sheet both melting and calving ice into the ocean.

The study had two major findings:

• First, the scientists were able to provide new estimates of annual ice loss at high spatial resolution.

• Second, the research revealed that current models fail to accurately capture how the entire Greenland Ice Sheet is changing and contributing to rising oceans.

The second point is crucial to climate change modelers.

Today's simulations use the activity of four well-studied glaciers -- Jakobshavn, Helheim, Kangerlussuaq and Petermann -- to forecast how the entire ice sheet will dump ice into the oceans.

But the new research shows that activity at these four locations may not be representative of what is happening with glaciers across the ice sheet. In fact, glaciers undergo patterns of thinning and thickening that current climate change simulations fail to address, Csatho says.

"There are 242 outlet glaciers wider than 1.5 km on the Greenland Ice Sheet, and what we see is that their behavior is complex in space and time," Csatho says. "The local climate and geological conditions, the local hydrology -- all of these factors have an effect. The current models do not address this complexity."

The team identified areas of rapid shrinkage in southeast Greenland that today's models don't acknowledge. This leads Csatho to believe that the ice sheet could lose ice faster in the future than today's simulations would suggest.

The results will be published on Dec. 15 in the Proceedings of the National Academy of Sciences.

How much ice is the Greenland Ice Sheet losing?

To analyze how the height of the ice sheet was changing, Csatho and UB research professor and photogrammetrist Anton Schenk, PhD, developed a computational technique called Surface Elevation Reconstruction And Change detection to fuse together data from NASA satellite and aerial missions.

The analysis found that the Greenland Ice Sheet lost about 243 metric gigatons of ice annually -- equivalent to about 277 cubic kilometers of ice per year -- from 2003-09, the period for which the team had the most comprehensive data. This loss is estimated to have added about 0.68 millimeters of water to the oceans annually.

The figures are averages, and ice loss varied from year to year, and from region to region.

Why are today's projections of sea level rise flawed, and how can we fix them?

Glaciers don't just gradually lose mass when the temperature rises. That's one reason it's difficult to predict their response to global warming.

In the study, scientists found that some of Greenland's glaciers thickened even when the temperature rose. Others exhibited accelerated thinning. Some displayed both thinning and thickening, with sudden reversals.

As a step toward building better models of sea level rise, the research team divided Greenland's 242 glaciers into 7 major groups based on their behavior from 2003-09.

"Understanding the groupings will help us pick out examples of glaciers that are representative of the whole," Csatho says. "We can then use data from these representative glaciers in models to provide a more complete picture of what is happening."

In a new project, she and colleagues are investigating why different glaciers respond differently to warming. Factors could include the temperature of the surrounding ocean; the level of friction between a glacier and the bedrock below; the amount of water under a glacier; and the geometry of the fjord.

"The physics of these processes are not well understood," Csatho says.

The NASA missions: A colossal undertaking

The study combined data from various NASA missions, including:

• NASA's Ice, Cloud and Land Elevation Satellite (ICESat), which measured the ice sheet's elevation multiple times a year at each of the nearly 100,000 locations from 2003-09.

• NASA's, massive aerial survey that employs highly specialized research aircrafts to collect data at less frequent intervals than ICESat. These missions began measuring the Greenland Ice Sheet's elevation in 1993. Operation IceBridge was started in 2009 to bridge the time between ICESat-1 and ICESat-2, and will continue until at least 2017, when NASA's next generation ICESat-2 satellite is expected to come online.

Csatho says the new study shows why careful monitoring is critical: Given the complex nature of glacier behavior, good data is crucial to building better models.

Collaborators

Besides Csatho, Schenk and van der Veen, the project included additional researchers from the University at Buffalo, Utrecht University in The Netherlands, the Technical University of Denmark and Florida Atlantic University.

Source:  University at Buffalo

NASA's CATS eyes clouds, smoke and dust from the space station

The interactions between clouds and aerosols are illustrated in this image, taken by retired astronaut Chris Hadfield onboard the International Space Station. It shows contrails produced by aircraft (bright streaks) over the ocean. Credit: NASA/Chris Hadfield

Turn on any local TV weather forecast and you can get a map of where skies are blue or cloudy. But for scientists trying to figure out how clouds affect Earth's environment, what's happening inside that shifting cloud cover is critical and hard to see.

To investigate the layers and composition of clouds and tiny airborne particles like dust, smoke and other atmospheric aerosols, , scientists at NASA's Goddard Space Flight Center in Greenbelt, Maryland have developed an instrument called the Cloud-Aerosol Transport System, or CATS. The instrument, which launches to the International Space Station in December 2014, will explore new technologies that could also be used in future satellite missions.

From space, streaks of white clouds can be seen moving across Earth's surface. Other tiny solid and liquid particles called aerosols are also being transported around the atmosphere, but these are largely invisible to our eyes. Aerosols are both natural and man-made, and include windblown desert dust, sea salt, smoke from fires, sulfurous particles from volcanic eruptions, and particles from fossil fuel combustion.

Currently, scientists get a broad picture of clouds and air quality conditions in the atmosphere and generate air quality forecasts by combining satellite, aircraft, and ground-based data with sophisticated computer models. However, most datasets do not provide information about the layered structure of clouds and aerosols.

CATS will provide data about aerosols at different levels of the atmosphere. The data are expected to improve scientists' ability to track different cloud and aerosol types throughout the atmosphere. These datasets will be used to improve strategic and hazard-warning capabilities of events in near real-time, such as tracking plumes from dust storms, volcanic eruptions, and wildfires. The information could also feed into climate models to help understand the effects of clouds and aerosols on Earth's energy balance.

Clouds and aerosols reflect and absorb energy from the sun in a complex way. For example, when the sun's energy reaches the top of the atmosphere, clouds can reflect incoming sunlight, cooling Earth's surface. However, clouds can also absorb heat emitted from Earth and re-radiate it back down, warming the surface. The amount of warming or cooling is heavily dependent on the height, thickness, and structure of clouds in the atmosphere above.

"Clouds are one of the largest uncertainties in predicting climate change," said Matt McGill, principal investigator and payload developer for CATS at Goddard. "For scientists to create more accurate models of Earth's current and future climate, they'll have to include more accurate representations of clouds."

That's where a new instrument like CATS comes in. CATS is a lidar -- similar to a radar, but instead of sending out sound, lidars use light. CATS will send a laser pulse through the atmosphere towards a distant object like a cloud droplet or aerosol particle. Once the energy reaches the object, some of the energy is reflected back to the lidar receiver. Scientists can calculate the distance between the instrument and the object, based on the time it takes the energy to return to the receiver, thereby determining the altitudes of cloud and aerosol layers. The intensity of this return pulse also allows scientists to infer other properties, such as the composition of clouds, and the abundance and sizes of aerosols,.

In 2006 NASA launched the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations, or CALIPSO, spacecraft -- a joint mission between NASA and France's space agency, the Centre National d'Études Spatiales. CALIPSO carries a lidar that provides vertical distributions and properties of clouds and aerosols along a flight track. However, the CALIPSO lidar has exceeded its three-year prime mission and has been using its backup laser since 2009.

A unique opportunity to continue gathering this type of data presented itself in 2011 when the International Space Station Progam's NASA Research Office offered scientists at Goddard a mounting location aboard the space station for a new lidar instrument -- CATS, and provided the funding for its construction.

Designed to operate for at least six months, CATS has a goal of operating for three years. With beams at three wavelengths (1064, 532, and 355 nanometers), CATS will be used to derive a variety of properties of cloud and aerosol layers. These properties include layer height, layer thickness, and at least coarse information on the type of aerosols and cloud in various atmospheric layers.

CATS will orbit aboard the space station, which flies at an altitude between 230 miles (375 kilometers) and 270 miles (435 kilometers) above Earth's surface at a 51-degree inclination. This unique orbit path will allow the CATS instrument to observe locations at different times of day and allow scientists to study day-to-night changes in cloud and aerosol effects from space.

Studying clouds and aerosols won't just help scientists study the climate, it's also a chance to investigate air quality and how atmospheric particles affect daily life. That can range from volcano ash plumes, to dust storms, to pollution outbreaks, to wildfires, like the California Rim Fire in September 2013 that choked Yosemite National Park during the busy Labor Day weekend. These particles pose health risks to populations, especially to the medically vulnerable, By infusing CATS data directly into aerosol models, data from CATS can make a difference in tracking and responding to impacts of similar events in the future.

Source:  NASA/Goddard Space Flight Center